The present honeycomb structure used by the Ford Motor Company as a substrate for an auto exhaust catalyst has approximately 47 openings per square centimeter of front face surface. These substrates are manufactured from a ceramic material, essentially cordierite, and are made by an extrusion process. The resultant honeycomb has a plurality of cells which run the axial length of the honeycomb. These cells have a square cross section with an inside dimension of about 1.1 mm and are separated from one another by walls that are 150-250 micron thick. These cell walls are approximately 35-40% porous, wih the pores having an average diameter of about 10 microns.
It struck me that a honeycomb structure could be used as a separator to form an overall lightweight fuel cell. The honeycomb separator would be used in a manner such that its cells define a plurality of separate fuel compartments and oxidant compartments. With alternate cells being fuel and oxidant compartments, the structure allows for a high interface area between opposite compartments with considerable overall strength.
I am aware of U.S. Pat. No. 3,206,332 for an "Electrolytic Cell Structure". This patent shows an electrolyte-support structure in the form of a plurality of triangular-shaped parallel cells 10 of a ceramic material. The cells 10 are used to support spaced-apart electrodes, one electrode being the right hand electrode identified by the numeral 1 and the other electrode being the left hand electrode identified by the numeral 1'. The right hand electrode is the oxidant electrode, and the left hand electrode is the fuel electrode. The cells 10 are impregnated throughout their entire volume with a suitable electrolyte so that the necessary electrochemical reactions may take place to cause a current to flow to an exterior electrical load. The walls of the cells are made porous so that the oxidation products of the cell may escape therefrom.
The U.S. Pat. No. 3,206,322 does not, in any manner, propose that the electrolyte be retained only in the cell walls of the cells 10 and that the individual volume defined by the various walls of the cells be alternately formed as oxidant compartments and as fuel compartments, as I am teaching in this specification. I am unaware of any proposal to use a honeycomb separator as the device for defining the separate fuel and oxidant compartments of a fuel cell.